Ammonia-free denitration synergistic CO removal system

Abstract

The utility model belongs to the field of flue gas treatment, and particularly relates to an ammonia-free denitration and CO removal synergetic system. The ammonia-free denitration synergistic CO removal system comprises a CO storage tank and an ammonia-free denitration synergistic CO removal reactor; the CO storage tank is used for adding CO into flue gas to obtain balanced flue gas; the ammonia-free denitration and CO removal synergistic reactor sequentially comprises a CO-NOx denitration catalyst layer and an optional CO removal catalyst layer along the flow direction of flue gas; the CO-NOx denitration catalyst layer is used for adsorbing and balancing NOX and CO in the flue gas and enabling the NOX and the CO to be subjected to an oxidation-reduction reaction to obtain denitrified flue gas; the CO removal catalyst layer is used for removing CO in the denitrified flue gas to obtain CO-removed flue gas. The ammonia-free denitration and CO removal synergistic system not only can avoid ammonia escape, but also can ensure that CO and NOX have high removal efficiency.

Description

TECHNICAL FIELD

[0001] The utility model belongs to the field of flue gas treatment relates to a kind of ammonia-free denitration collaborative CO removal system. BACKGROUND

[0002] Nitrogen oxide is harmful component in air, the general name of NO and NO2, expressed as NOx.

[0003] Currently, the nitrogen oxide removal technology widely used in industrial production is selective non-catalytic reduction (SNCR) and selective catalytic reduction (SCR).

[0004] SNCR process uses ammonia or urea as reducing agent, under high temperature condition of 850-1000 ℃, dilute reducing agent solution is sprayed into flue gas for reaction, so that NOx in it is converted into nitrogen, without introducing catalyst, denitration reaction can be completed. SNCR technology is simple, low investment, and has good application in some fields, but its limitations are relatively large. First, the technology cannot remove high concentration NO X , general removal efficiency is about 40-60%. Second, it needs suitable temperature range and sufficient reaction time, generally requires reaction at high temperature of 850-1000 ℃, and the residence time of reducing agent ammonia under temperature interval needs more than 0.3 s to achieve effective denitrogenation effect.

[0005] SCR process is the most mature flue gas denitration process at home and abroad, with the highest denitration efficiency and the most widely application. SCR process mainly introduces reducing agent NH3 into flue gas under certain temperature and catalyst, to reduce NOx in flue gas into harmless nitrogen (N2) and water (H2O), due to the introduction of catalyst, reaction can be carried out at temperature interval of 280-400 ℃.

[0006] The main reactions of SCR process are as follows:

[0007] 4NH3+4NO+O2=4N2+6H2O

[0008] 8NH3+6NO2=7N2+12H2O

[0009] 4NH3+2NO2+O2=3N2+6H2O

[0010] The SCR process requires spraying a reducing agent ammonia into the flue gas, and under the action of a catalyst, nitrogen oxides and the reducing agent undergo an oxidation-reduction reaction. In fact, in the process of operation of a general flue gas treatment system, the oxidation-reduction reaction of NOx and ammonia is affected by many factors such as reaction temperature, catalyst dosage, ammonia consumption, mixing degree of ammonia and flue gas, and uniformity of flue gas entering each reactor, and often excessive ammonia is sprayed to reduce the NOx concentration at the outlet of the denitrification, thereby causing excessive ammonia escape. The escaped ammonia is discharged into the atmosphere, which will further cause pollution.

[0011] In summary, whether SNCR or SCR is used for denitrogenation, a reducing agent ammonia needs to be sprayed. In actual operation, due to factors such as the mixing degree of ammonia and flue gas and reaction temperature, excessive reducing agent ammonia is sprayed to ensure that the nitrogen oxides at the outlet of the flue gas meet the standards, which leads to the escape of the sprayed ammonia into the subsequent process section and finally into the atmosphere. The escaped ammonia is easy to react with sulfur trioxide in the flue gas to form ammonium bisulfate, which is a high-viscosity liquid material that is easy to condense and deposit on the surface of the heat exchange elements of the air preheater, easily adhere to the fly ash particles in the flue gas, block the passages of the heat exchange elements, increase the resistance of the air preheater, and affect the heat exchange effect.

[0012] CN217614012U discloses a NOx-CO collaborative purification system, which proposes spraying ammonia water, liquid ammonia, urea and other reducing agents into flue gas containing CO and NO X , and simultaneously removing NO X and CO in the catalyst bed, and the catalyst material in the catalyst bed is a honeycomb extrusion type, a honeycomb coating type or a filter tube coating type. However, although this system can simultaneously achieve the effects of denitrogenation and CO removal, it still needs to introduce ammonia, and the problem of ammonia escape cannot be avoided. CN114642963A discloses a method for removing NOx from sintering flue gas, which proposes mixing the dust-removing and desulfurized sintering flue gas with high-temperature air, and then introducing the mixture into a denitrification tower, so that the CO and NOx in the flue gas undergo oxidation-reduction reaction under the action of a vanadium-titanium-based honeycomb catalyst, thereby achieving ammonia-free denitrification of the sintering flue gas. Although this process does not need to introduce ammonia as a reducing agent, it can avoid the problem of ammonia escape, but it is often difficult to simultaneously ensure that CO and NO X have high removal efficiency. Practical new type content

[0013] The purpose of the present utility model is to overcome the problem that when the existing system is used to treat flue gas containing CO and NO X , ammonia escape cannot be avoided and CO and NO X both have high removal efficiency, and to provide an ammonia-free denitrification and CO removal system, which can not only avoid ammonia escape, but also ensure that CO and NO X both have high removal efficiency.

[0014] The inventors of the present utility model have found through in-depth research that the method disclosed in CN114642963A mentioned in the background art cannot simultaneously ensure the removal of CO and NOx X with high removal efficiency, mainly because in actual production, the content of CO and NOx X in flue gas usually differs greatly. In the examples mentioned in the patent application, the concentration of NOx is ≤350 mg / Nm 3 , and the concentration of CO is as high as 3000-8000 ppm (equivalent to 4000-11000 mg / Nm 3 ). This results in that excessive CO and a small amount of NOx X cannot be completely consumed by reaction, and a large amount of unreacted CO is inevitably produced. Moreover, the system only uses a single vanadium-titanium-based honeycomb catalyst. This type of catalyst is a conventional CO-NOx denitration catalyst. Due to the selectivity of the catalyst, it cannot ensure high CO removal efficiency under the condition of high denitration efficiency.

[0015] Based on the problems existing in the above prior art, the inventors of the present utility model have creatively found through extensive and in-depth research that by adding a CO storage tank and setting two catalyst layers (a CO-NOx denitration catalyst layer and an optional CO removal catalyst layer) in the reactor, various flue gases can be effectively treated, and CO and NOx X can be simultaneously and efficiently removed. Specifically, if the CO concentration in the flue gas is low (the volume ratio of CO to NOx is less than 1), the reducing agent concentration is not sufficient during the denitration process, and NOx X cannot be completely removed. In this case, CO needs to be sprayed into the flue gas through the CO storage tank to increase the volume ratio of CO to NOx in the flue gas to more than 1, so as to ensure that the denitration efficiency meets the standard. If the CO in the flue gas is excessive (the volume ratio of CO to NOx is greater than 1), denitration can be realized through the CO-NOx denitration catalyst layer first, and then the CO in the flue gas is converted into CO2 through the action of the CO removal catalyst to remove CO, thereby ensuring the simultaneous removal of NOx X and CO in the flue gas. The entire system uses the CO contained in the flue gas and the additional CO from the CO storage tank as the reducing agent, and does not need to introduce ammonia as the reducing agent for denitration, thereby avoiding the problem of ammonia escape. Therefore, it is a denitration reaction without ammonia. The excessive CO is removed through the CO removal catalyst layer arranged at the rear end, thereby forming an ammonia-free denitration system that simultaneously removes CO. This system has no ammonia escape problem and has the advantages of high denitration and CO removal efficiency. By arranging the CO storage tank, it can adapt to flue gas with different proportions of NOx X and CO. Based on this, the present utility model is completed.

[0016] Specifically, the ammonia-free denitration and CO removal system provided by the utility model includes a CO storage tank and an ammonia-free denitration and CO removal reactor; the CO storage tank is used for adding CO into flue gas to obtain balanced flue gas; the ammonia-free denitration and CO removal reactor includes a CO-NOx denitration catalyst layer and an optional CO removal catalyst layer in sequence along the flue gas flow direction; the CO-NOx denitration catalyst layer is used for adsorbing NOx in the balanced flue gas and causing oxidation-reduction reaction of NOx and CO to obtain denitration flue gas; and the CO removal catalyst layer is used for removing CO in the denitration flue gas to obtain CO removal flue gas. X

[0017] The ammonia-free denitration and CO removal system provided by the utility model uses CO in the flue gas and additional CO introduced via the CO storage tank as a denitration reducing agent, does not need to introduce ammonia, avoids ammonia escape risk, fully considers the selectivity of the catalyst, makes the flue gas pass through the CO-NOx denitration catalyst layer first to make NOx in the flue gas be reduced to N2 by CO, maintains the denitration efficiency of the system at a high level, and then selectively passes through the CO removal catalyst layer to make CO in the flue gas be removed, thereby realizing efficient removal of NOx and CO.

[0018] In a preferred embodiment, the ammonia-free denitration and CO removal system further includes a desulfurization and dust removal device, a flue gas outlet of the desulfurization and dust removal device is communicated with a flue gas inlet of the ammonia-free denitration and CO removal reactor, and SO2 and dust in the flue gas are removed, at this time, CO removal catalyst poisoning and failure can be avoided, and CO removal efficiency can be improved.

[0019] In a preferred embodiment, the ammonia-free denitration and CO removal system further includes a waste heat boiler, a raw material inlet of the waste heat boiler is communicated with a flue gas outlet of the ammonia-free denitration and CO removal reactor, and waste heat in the flue gas from the ammonia-free denitration and CO removal reactor is recovered, at this time, heat energy released in CO removal can be fully utilized, and the effect of energy saving and carbon reduction can be achieved. BRIEF DESCRIPTION OF DRAWINGS

[0020] Figure 1 A schematic diagram of the ammonia-free denitration and CO removal system provided by the utility model is shown.

[0021] Mark: 10: CO storage tank; 20: ammonia-free denitration and CO removal reactor; 201: CO-NOx denitration catalyst layer; 202: CO removal catalyst layer; 203: rectifier grid; 30: desulfurization and dust removal device; 40: waste heat boiler; 50: injection grid. DETAILED DESCRIPTION

[0022] To make the purpose, technical scheme and advantages of the utility model clearer, the utility model embodiments will be further described in detail below with reference to the drawings.​

[0023] The technical solutions of the present utility model will be clearly and completely described below with reference to the accompanying drawings of the embodiments. Obviously, the described embodiments are only some embodiments of the present utility model, not all embodiments. Based on the embodiments of the present utility model, all other embodiments obtained by those skilled in the art without creative effort are within the protection scope of the present utility model.

[0024] In the accompanying drawings, directional indications (such as up and down) are used to explain that the various components of this invention are relative rather than absolute. These descriptions are appropriate when these components are in the positions shown in the drawings. If the description of the positions of these elements changes, these directional indications will also change accordingly.

[0025] like Figure 1 As shown, the ammonia-free denitrification and CO removal system provided by this utility model includes a CO storage tank 10 and an ammonia-free denitrification and CO removal reactor 20; the CO storage tank 10 is used to add CO to the flue gas to obtain a balanced flue gas; the ammonia-free denitrification and CO removal reactor 20 includes, along the flue gas flow direction, a CO-NOx denitrification catalyst layer 201 and an optional CO removal catalyst layer 202; the CO-NOx denitrification catalyst layer 201 is used to adsorb NO in the balanced flue gas. X The process involves reacting CO with the nitrogen oxides to induce a redox reaction, resulting in denitrified flue gas. The CO removal catalyst layer 202 is used to remove CO from the denitrified flue gas, yielding denitrified flue gas. The CO storage tank 10 can be selectively opened. If the CO proportion in the flue gas is low (the volume ratio of CO to NOx is less than 1), the CO storage tank 10 is opened, injecting CO into the flue gas to ensure sufficient reducing agent. If the CO proportion in the flue gas is high (the volume ratio of CO to NOx is greater than 1), the CO storage tank 10 is closed, allowing the flue gas to use its own CO as a reducing agent for complete denitrification. This method can handle various proportions of NOx. X-CO flue gas. The ammonia-free denitration and CO removal system does not need to introduce additional reducing agent ammonia, and there is no ammonia escape problem. Instead, CO in the flue gas and CO from the CO storage tank are used as reducing agents. Under the action of the CO-NOx denitration catalyst, the removal of nitrogen oxides in the flue gas and the reduction or removal of CO are realized. The optional setting of the CO removal catalyst layer means that whether the CO removal catalyst layer 202 is set should be determined according to the actual situation. If the denitration process cannot completely consume CO, the CO removal catalyst needs to be further used to remove CO. At this time, the ammonia-free denitration and CO removal reactor needs to be provided with a CO removal catalyst layer 202. If the denitration process can basically completely consume CO, the CO removal step does not need to be introduced. At this time, the ammonia-free denitration and CO removal reactor does not need to be provided with a CO removal catalyst layer 202, so as to realize the simultaneous and efficient removal of nitrogen oxides and CO.

[0026] In the utility model, as described above, the CO removal catalyst layer 202 can be selectively arranged, if the CO cannot be completely consumed in the denitration process, the CO removal catalyst layer 202 needs to be arranged, if the CO can be basically completely consumed in the denitration process, the CO removal catalyst layer 202 does not need to be arranged.When the CO-NOx denitration catalyst layer 201 and the CO removal catalyst layer 202 are simultaneously included in the ammonia-free denitration and CO removal reactor 20, the arrangement position of the CO-NOx denitration catalyst layer 201 and the CO removal catalyst layer 202 is not particularly limited, as long as the flue gas flows through the CO-NOx denitration catalyst layer 201 and the CO removal catalyst layer 202 in sequence, for example, the CO-NOx denitration catalyst layer and the CO removal catalyst layer can be arranged in the upper layer and the lower layer of the ammonia-free denitration and CO removal reactor 20 respectively, at this time, the flue gas flows through the ammonia-free denitration and CO removal reactor 20 from top to bottom, the CO-NOx denitration catalyst layer and the CO removal catalyst layer can also be arranged in the lower layer and the upper layer of the ammonia-free denitration and CO removal reactor 20 respectively, at this time, the flue gas flows through the ammonia-free denitration and CO removal reactor 20 from bottom to top.In one specific embodiment, the CO-NOx denitration catalyst layer 201 is arranged in the upper layer of the ammonia-free denitration and CO removal reactor 20, the CO removal catalyst layer 202 is arranged in the lower layer of the ammonia-free denitration and CO removal reactor 20, the flue gas inlet is arranged between the top of the ammonia-free denitration and CO removal reactor 20 and the CO-NOx denitration catalyst layer 201, and the flue gas outlet is arranged between the bottom of the ammonia-free denitration and CO removal reactor and the CO removal catalyst layer 202.In addition, the thickness of the CO-NOx denitration catalyst layer 201 is preferably 800mm-1200mm, such as 800mm, 850mm, 900mm, 950mm, 1000mm, 1050mm, 1100mm, 1150mm, 1200mm and the like.The thickness of the CO removal catalyst layer 202 is preferably 800mm-1200mm, such as 800mm, 850mm, 900mm, 950mm, 1000mm, 1050mm, 1100mm, 1150mm, 1200mm and the like.

[0027] In the utility model, the nitrogen oxides in the flue gas mainly exist in the form of NO, first, under the action of the CO-NOx denitration catalyst, NO and CO are adsorbed on the catalyst surface to form adsorbed NO and adsorbed CO, adsorbed NO is decomposed into adsorbed N and adsorbed O, adsorbed N and adsorbed NO react to generate N2, and adsorbed O and adsorbed CO combine to generate CO2, and the main chemical reaction formula is as follows:

[0028] 2NO+CO→N2O+CO2

[0029] N2O+CO→N2+CO2。

[0030] In the utility model, flue gas passes through CO-NO X The concentration of nitrogen oxides in flue gas is reduced after passing through the denitration catalyst, and the emission requirement is reached, but because the CO concentration in flue gas of some typical industries (for example, steel sintering flue gas) is relatively high, generally reaching 5000-10000ppm, a large amount of unreacted CO remains in flue gas after participating in the denitration catalytic reduction reaction, therefore, it is necessary to make the denitrogen flue gas further pass through the CO removal catalyst layer, so that the CO is converted into CO2 in the presence of the CO removal catalyst.

[0031] In the utility model, after CO removal, the temperature of flue gas is increased due to the heat released by the conversion of CO into CO2. Therefore, if the ammonia-free denitration system in cooperation with CO removal includes a CO removal catalyst layer, it is preferably further provided with a waste heat boiler for recycling the waste heat in flue gas, at this time, the energy saving and carbon reduction effect can be ensured on the basis of realizing the simultaneous removal of nitrogen oxides and CO. The flue gas after waste heat recovery is drawn by an induced draft fan to a chimney for emission.

[0032] In the utility model, the ammonia-free denitration system in cooperation with CO removal reactor is preferably further provided with a flow regulation grid 203, the vertical height of the flow regulation grid 203 is located between the flue gas inlet and the CO-NOx denitration catalyst layer, for adjusting the flow field distribution of the balanced flue gas entering the CO-NOx denitration catalyst layer, at this time, the feeding is more uniform, which is more conducive to the full removal of NO X and CO in flue gas. The mesh size of the flow regulation grid can be 50mm-350mm, such as 50mm, 100mm, 150mm, 200mm, 250mm, 300mm, 350mm or any value therebetween.

[0033] In the utility model, the mature CO removal catalyst takes noble metal as active component, these active components are easily affected by SO2 and dust in the flue gas of a heating furnace, leading to catalyst poisoning or blockage failure. For this, the ammonia-free denitration system in cooperation with CO removal system provided by the utility model is preferably further provided with a desulfurization and dust removal device 30, the flue gas outlet of the desulfurization and dust removal device 30 is communicated with the flue gas inlet of the ammonia-free denitration system in cooperation with CO removal reactor 20, for removing SO2 and dust in flue gas, at this time, the catalytic activity of the CO catalyst can be ensured, and the CO removal effect is improved.

[0034] In the utility model, the ammonia-free denitration system in cooperation with CO removal system is preferably further provided with a spray grid 50, the spray grid 50 is arranged on the pipeline communicated between the flue gas outlet of the desulfurization and dust removal device 30 and the flue gas inlet of the ammonia-free denitration system in cooperation with CO removal reactor 20, for adjusting the flow field distribution of CO entering flue gas from the CO storage tank 10, at this time, the CO can be more uniformly mixed into flue gas, which is more conducive to the full removal of NO Xand CO.

[0035] In the optimal embodiment of the utility model, the ammonia-free denitration and CO removal system includes a desulfurization and dust removal device 30, a CO storage tank 10, an ammonia-free denitration and CO removal reactor 20, and a waste heat boiler 40; the ammonia-free denitration and CO removal reactor 20 has, from top to bottom, a flow regulation grid 203, a CO-NOx denitration catalyst layer 201, and an optional CO removal catalyst layer 202; a flue gas inlet is arranged between the top of the ammonia-free denitration and CO removal reactor and the flow regulation grid 203; a flue gas outlet is arranged between the bottom of the ammonia-free denitration and CO removal reactor and the CO removal catalyst layer; the flue gas outlet of the desulfurization and dust removal device 30 is in communication with the flue gas inlet of the ammonia-free denitration and CO removal reactor 20, and a spray grid 50 is arranged on the communication pipeline of the two; the spray grid 50 is used to spray CO from the CO storage tank 10 into the flue gas; the flue gas outlet of the ammonia-free denitration and CO removal reactor 20 is in communication with the flue gas inlet of the waste heat boiler 40; the opening and closing of the CO storage tank 10 is controlled by a spraying device.

[0036] When working, the flue gas containing NO X and CO is subjected to desulfurization and dust removal in the desulfurization and dust removal device 30 to remove substances that can affect the catalytic efficiency of the subsequent catalyst. X The CO storage tank 10 stores CO, which is selectively sprayed into the flue gas through the spray grid 50 according to the proportion of NO X and CO in the flue gas, so that the reducing agent in the flue gas is sufficient to ensure the removal efficiency of NO X . The flue gas containing a certain proportion of NO X and CO passes through the flow regulation grid 203 to make the flue gas flow field more uniform, and then passes through the CO-NOx denitration catalyst layer 201, where NO X and CO in the flue gas are adsorbed on the CO-NOx denitration catalyst layer 201 to undergo a redox reaction. XBoth NO and CO can be removed, wherein the CO-NOx denitration catalyst removes all of the NO X and part of the CO, the catalyst component of which can be designed for denitration function, and a higher denitration efficiency can be achieved, and the CO removal catalyst removes the remaining CO in the flue gas, and the amount of the CO removal catalyst can be designed according to the amount of CO to ensure that the CO removal efficiency meets the standard. Similarly, the CO removal catalyst layer 202 is only for the removal of CO, and the component design thereof only needs to consider the removal of CO, and the removal efficiency is higher. After the removal of CO, the heat released by the flue gas absorption reaction increases the temperature, and therefore the flue gas is further introduced into the subsequent waste heat boiler 40 to recover heat. The high-temperature flue gas passes through the heat exchanger in the waste heat boiler 40 to transfer heat, thereby achieving the effect of recovering heat energy. The flue gas after heat recovery is introduced into the chimney by the induced draft fan for emission. The temperature of the flue gas passing through the waste heat boiler 40 is reduced, thereby reducing the temperature resistance requirement of the downstream equipment and the investment cost.

[0037] When the system is used for ammonia-free denitration and CO removal, the specific method comprises selectively introducing CO into the flue gas to obtain balanced flue gas, the volume ratio of CO to NOx in the balanced flue gas is controlled to be greater than or equal to 1, and then the balanced flue gas passes through the CO-NOx denitration catalyst layer to adsorb NO X and CO and causes oxidation-reduction reaction to obtain denitration flue gas, and then the denitration flue gas selectively passes through the CO removal catalyst layer to remove CO to obtain CO removal flue gas.

[0038] The CO-NOx denitration catalyst contained in the CO-NOx denitration catalyst layer and the CO removal catalyst contained in the CO removal catalyst layer can be conventional choices in the art, and can be commercially available or prepared by various methods known in the art. For example, the active component of the CO-NOx denitration catalyst can be noble metal I and / or transition metal. The noble metal I can include at least one of Pt, Pd, Rh, Ag and Ir. The transition metal can include at least one of Fe, Cu, Ce and Co. The CO-NOx denitration catalyst can be a vanadium-titanium-based catalyst. The active component of the CO removal catalyst can be noble metal II. The noble metal II can include at least one of Pt, Pd, Rh, Ag and Ir. The terms "I" and "II" are only used to distinguish the noble metals introduced at different positions for the purpose of description, and have no other special meanings.

[0039] In the utility model, the conditions of the oxidation-reduction reaction are preferably that the temperature is 220 DEG C ~ 350 DEG C, the pressure is -8000Pa ~ -2000Pa, and the reaction is instantaneous reaction. The conditions of the removal of CO are preferably that the temperature is 220 DEG C ~ 350 DEG C, the pressure is -8000Pa ~ -2000Pa, and the reaction is instantaneous reaction. The pressures are all gauge pressures.

[0040] The utility model will be described in detail through examples.

[0041] Example one

[0042] The ammonia-free denitration and CO removal system adopted in the example includes a desulfurization and dust removal device 30, a CO storage tank 10, an ammonia-free denitration and CO removal reactor 20, and a waste heat boiler 40. The ammonia-free denitration and CO removal reactor 20 has, from top to bottom, in sequence, a flow regulation grid 203, a CO-NOx denitration catalyst layer 201, and a CO removal catalyst layer 202. A flue gas inlet is arranged between the top of the ammonia-free denitration and CO removal reactor and the flow regulation grid 203. A flue gas outlet is arranged between the bottom of the ammonia-free denitration and CO removal reactor and the CO removal catalyst layer. The flue gas outlet of the desulfurization and dust removal device 30 is in communication with the flue gas inlet of the ammonia-free denitration and CO removal reactor 20, and a spray grid 50 is arranged on the communication pipeline between the two. The spray grid 50 is used to spray CO from the CO storage tank 10 into the flue gas. The flue gas outlet of the ammonia-free denitration and CO removal reactor 20 is in communication with the flue gas inlet of the waste heat boiler 40. The opening and closing of the CO storage tank 10 is controlled by a spraying device. The CO-NOx denitration catalyst used is a vanadium-titanium-based catalyst mentioned in CN11464296A (the vanadium-titanium-based catalyst is composed of 72wt% TiO2, 2.45wt% MnO2, 10.67wt% V2O5, 7.77wt% CeO2, 2.35wt% Co2O3, and 4.34wt% glass fiber). The thickness of the CO-NOx denitration catalyst layer 201 is 1000mm. The CO removal catalyst used is a commercially available honeycomb noble metal catalyst from Hubei Kerong, and the material used is a noble metal material Pd. The thickness of the CO removal catalyst layer 202 is 1000mm.

[0043] Taking an industrial flue gas treatment system designed for a wind volume of 1000000m 3 / h as an example, the concentration of NO X in the flue gas is 350mg / Nm 3 , 90% of which is NO, and the rest is NO2. The concentration of CO is 8000mg / Nm 3 , and the temperature of the flue gas is 280℃.

[0044] First, the flue gas is subjected to desulfurization and dust removal treatment by the desulfurization and dust removal device 30, so that the concentrations of SO2 and dust in the flue gas are controlled at 10mg / Nm 3 and below and 5mg / Nm 3 and below, respectively. Since the concentration of CO in the flue gas is relatively high compared with that of NO XThe concentration is much higher, eliminating the need to open the CO storage tank 10 and the injection grid 50. The flue gas after desulfurization and dust removal passes through the rectifying grid 203 to make the flow field more uniform, which is beneficial for subsequent reaction with the catalyst. The flue gas after desulfurization and dust removal passes through the CO-NOx denitrification catalyst layer 201. Nitrogen oxides in the flue gas mainly exist in the form of NO. NO and CO are adsorbed on the catalyst surface to form adsorbed NO and adsorbed CO. Adsorbed NO decomposes into adsorbed N and adsorbed O. Adsorbed N and adsorbed NO react to generate N2, while adsorbed O combines with adsorbed CO to generate CO2. Under the action of the CO-NOx denitrification catalyst, NO in the flue gas... X More than 92% were removed, meeting the export NO standards. X Less than 30 mg / Nm 3 The emission targets were met. The CO concentration in the flue gas after denitrification was reduced to approximately 7800 mg / Nm³. 3 This allows it to pass through the CO removal catalyst layer 202. Under the action of the CO removal catalyst, the CO removal efficiency in the flue gas is approximately 90%, and the outlet CO concentration is reduced to approximately 800 mg / Nm³. 3 This catalytic reaction is a typical exothermic reaction, raising the flue gas temperature to 330℃. It is then fed into a waste heat boiler 40, where heat exchange reduces the flue gas temperature to 120℃. On one hand, the heat recovered through heat exchange can be utilized, saving energy. On the other hand, the reduced outlet flue gas temperature lowers the temperature resistance requirements of subsequent equipment, saving on equipment investment. The heat-exchanged flue gas is then discharged to the chimney by an induced draft fan and ultimately released into the atmosphere through the chimney.

[0045] Example 2

[0046] The ammonia-free denitration and CO removal system used in this embodiment includes a desulfurization and dust removal device 30, a CO tank 10, an ammonia-free denitration and CO removal reactor 20, and a waste heat boiler 40. The ammonia-free denitration and CO removal reactor 20 is internally provided with a flow regulation grid 203 and a CO-NOx denitration catalyst layer 201 from top to bottom. A flue gas inlet is arranged between the top of the ammonia-free denitration and CO removal reactor and the flow regulation grid 203. A flue gas outlet is arranged between the bottom of the ammonia-free denitration and CO removal reactor and the CO-NOx denitration catalyst layer 201. The flue gas outlet of the desulfurization and dust removal device 30 is in communication with the flue gas inlet of the ammonia-free denitration and CO removal reactor 20, and a spray grid 50 is arranged on the communication pipeline of the two. The spray grid 50 is used to spray CO in the CO tank 10 into the flue gas. The flue gas outlet of the ammonia-free denitration and CO removal reactor 20 is in communication with the flue gas inlet of the waste heat boiler 40. The opening and closing of the CO tank 10 is controlled by a spraying device. The CO-NOx denitration catalyst used is a vanadium-titanium-based catalyst mentioned in CN11464296A (the vanadium-titanium-based catalyst is composed of 72wt% TiO2, 2.45wt% MnO2, 10.67wt% V2O5, 7.77wt% CeO2, 2.35wt% Co2O3, and 4.34wt% glass fiber). The thickness of the CO-NOx denitration catalyst layer 201 is 1000mm. The CO removal catalyst used is a commercially available honeycomb noble metal catalyst from Hubei Kerun, and the material used is a noble metal material Pd. The thickness of the CO removal catalyst layer 202 is 1000mm.

[0047] The designed flue gas treatment system has a flue gas flow of 1000000m 3 / h. The NO X concentration in the flue gas is 350mg / Nm 3 , of which 90% is NO and the rest is NO2. The CO concentration in the flue gas is 50mg / Nm 3 , and the flue gas temperature is 280℃.

[0048] First, the flue gas is desulfurized and dusted by the desulfurization and dust removal device 30 to control the SO2 and dust concentrations in the flue gas to be less than or equal to 10mg / Nm 3 and 5mg / Nm 3 respectively. Since the CO concentration in the flue gas is much lower than the NO X concentration, CO in the CO tank 10 is injected into the flue gas through the spray grid 50, so that CO and NO XThe volume ratio reaches 1:1. The flue gas after desulfurization and dust removal passes through a rectifier grid 203 to make the flow field more uniform, which is beneficial for subsequent reaction with the catalyst. The flue gas after desulfurization and dust removal passes through the CO-NOx denitrification catalyst layer 201. Nitrogen oxides in the flue gas mainly exist in the form of NO. NO and CO are adsorbed on the catalyst surface to form adsorbed NO and adsorbed CO. Adsorbed NO decomposes into adsorbed N and adsorbed O. Adsorbed N and adsorbed NO react to generate N2, while adsorbed O combines with adsorbed CO to generate CO2. Under the action of the CO-NOx denitrification catalyst, NO in the flue gas... X More than 92% were removed, meeting the export NO standards. X Less than 30 mg / Nm 3 The emission standards are met. After denitrification, CO in the flue gas is basically completely removed, so there is no need to remove CO again through the CO removal catalyst layer 202. The flue gas then recovers waste heat through the waste heat boiler 40. The flue gas after heat exchange is directly discharged to the chimney by the induced draft fan and finally discharged into the atmosphere through the chimney.

[0049] Example 3

[0050] The ammonia-free denitrification and CO removal system used in this embodiment includes a desulfurization and dust removal device 30, a CO storage tank 10, an ammonia-free denitrification and CO removal reactor 20, and a waste heat boiler 40. The ammonia-free denitrification and CO removal reactor 20 is internally arranged from top to bottom with a rectifier grid 203, a CO-NOx denitrification catalyst layer 201, and a CO removal catalyst layer 202. A flue gas inlet is provided between the top of the ammonia-free denitrification and CO removal reactor and the rectifier grid 203. A flue gas outlet is provided between the bottom of the reactor and the CO removal catalyst layer; the flue gas outlet of the desulfurization and dust removal device 30 is connected to the flue gas inlet of the ammonia-free denitrification and CO removal reactor 20, and an injection grid 50 is provided on the connecting pipeline between the two. The injection grid 50 is used to inject CO drawn from the CO storage tank 10 into the flue gas. The flue gas outlet of the ammonia-free denitrification and CO removal reactor 20 is connected to the flue gas inlet of the waste heat boiler 40; the opening and closing of the CO storage tank 10 is controlled by the injection device. The CO-NOx denitrification catalyst used is the vanadium-titanium-based catalyst mentioned in CN11464296A (this vanadium-titanium-based catalyst is composed of 72wt% TiO2, 2.45wt% MnO2, 10.67wt% V2O5, 7.77wt% CeO2, 2.35wt% Co2O3 and 4.34wt% glass fiber). The thickness of the CO-NOx denitrification catalyst layer 201 is 1000 mm. The CO denitrification catalyst used is a commercially available honeycomb precious metal catalyst from Hubei Kerong, and the selected material is the precious metal Pd. The thickness of the CO denitrification catalyst layer 202 is 1000 mm.

[0051] Design wind volume 1000000m 3 / h industrial flue gas treatment system as an example, the NO X Concentration in flue gas is 350mg / Nm 3 , of which 90% is NO, and the rest is NO2, CO concentration is 100mg / Nm 3 , and the flue gas temperature is 280℃.

[0052] First, the flue gas is treated by desulfurization and dust removal device 30, and the concentration of SO2 and dust in the flue gas is controlled at 10mg / Nm 3 and 5mg / Nm 3 respectively. Because the CO concentration in the flue gas is much lower than the NO X concentration, the CO in the CO tank 10 is injected into the flue gas through the injection grid 50, so that the volume ratio of CO to NO X is 1.2:1. The desulfurized and dust-removed flue gas passes through the rectifying grid 203 to make the flow field more uniform, which is conducive to the subsequent reaction with the catalyst. The desulfurized and dust-removed flue gas passes through the CO-NOx denitration catalyst layer 201, and the nitrogen oxides in the flue gas mainly exist in the form of NO, NO and CO are adsorbed on the surface of the catalyst to form adsorbed NO and adsorbed CO, adsorbed NO is decomposed into adsorbed N and adsorbed O, adsorbed N and adsorbed NO react to generate N2, and adsorbed O combines with adsorbed CO to generate CO2. Under the action of the CO-NOx denitration catalyst, more than 92% of the NO X in the flue gas is removed, meeting the emission index of less than 30mg / Nm X of outlet NO 3 . The CO concentration in the denitration flue gas is about 50mg / Nm 3 , which makes it pass through the CO removal catalyst layer 202. Under the action of the CO removal catalyst, the CO removal efficiency in the flue gas is about 91%, and the outlet CO concentration is reduced to about 4.5mg / Nm 3 , the subsequent flue gas is sent to the waste heat boiler 40, and the flue gas temperature is reduced to 120℃ by heat exchange. On the one hand, the heat recovered by heat exchange can be utilized, saving energy. On the other hand, the reduction of the outlet flue gas temperature reduces the temperature resistance requirement of the subsequent equipment accordingly, which can save equipment investment. The flue gas after heat exchange is discharged to the chimney by the induced draft fan and finally discharged into the atmosphere by the chimney.

[0053] In summary, the ammonia-free denitration and CO removal system and method of example one, example two and example three can realize the simultaneous removal of NO X -CO, achieve more than 92% NO X -CO removal efficiency and more than 90% CO removal efficiency, and do not need to introduce reducing agent ammonia, without ammonia escape problem, while also can have heat energy recovery, with the effect of energy saving and carbon reduction.

[0054] Although the embodiments of the utility model have been shown and described above, it can be understood that the above-mentioned embodiments are exemplary and cannot be understood as limiting the utility model, and the ordinary skilled in the art can change, modify, replace and transform the above-mentioned embodiments within the scope of the utility model without departing from the principles and purposes of the utility model.

Claims

1. An ammonia-free denitration and CO removal system, characterized in that, The ammonia-free denitration and CO removal system comprises a CO storage tank and an ammonia-free denitration and CO removal reactor; the CO storage tank is used for adding CO into the flue gas to obtain balanced flue gas; the ammonia-free denitration and CO removal reactor comprises a CO-NOx denitration catalyst layer and an optional CO removal catalyst layer in sequence along the flue gas flow direction; the CO-NOx denitration catalyst layer is used for adsorbing NOx and CO in the balanced flue gas and causing redox reaction of the two to obtain denitration flue gas; and the CO removal catalyst layer is used for removing CO in the denitration flue gas to obtain CO removal flue gas. X and CO and causing redox reaction of the two to obtain denitration flue gas; and the CO removal catalyst layer is used for removing CO in the denitration flue gas to obtain CO removal flue gas.

2. The ammonia-free denitration and CO removal system according to claim 1, characterized in that, The CO-NOx denitration catalyst layer is arranged on the upper layer of the ammonia-free denitration and CO removal reactor, the CO removal catalyst layer is arranged on the lower layer of the ammonia-free denitration and CO removal reactor, the flue gas inlet is arranged between the top of the ammonia-free denitration and CO removal reactor and the CO-NOx denitration catalyst layer, and the flue gas outlet is arranged between the bottom of the ammonia-free denitration and CO removal reactor and the CO removal catalyst layer.

3. The ammonia-free denitration and CO removal system according to claim 1, characterized in that, The thickness of the CO-NOx denitration catalyst layer is 800mm-1200mm.

4. The ammonia-free denitration and CO removal system according to claim 1, characterized in that, The thickness of the CO removal catalyst layer is 800mm-1200mm.

5. The ammonia-free denitration and CO removal system according to claim 2, characterized in that, The ammonia-free denitration and CO removal reactor is further provided with a flow regulation grid, the vertical height of the flow regulation grid is between the flue gas inlet and the CO-NOx denitration catalyst layer, and the flow regulation grid is used for adjusting the flow field distribution of the balanced flue gas entering the CO-NOx denitration catalyst layer.

6. The ammonia-free denitration and CO removal system according to claim 5, characterized in that, The mesh size of the flow regulation grid is 50mm-350mm.

7. The ammonia-free denitration and CO removal system according to any one of claims 1 to 6, characterized by, The ammonia-free denitration and CO removal system further comprises a desulfurization and dust removal device, the flue gas outlet of the desulfurization and dust removal device is communicated with the flue gas inlet of the ammonia-free denitration and CO removal reactor, and the desulfurization and dust removal device is used for desulfurizing and dust removing the flue gas.

8. The ammonia-free denitration and CO removal system according to claim 7, characterized in that, The ammonia-free denitration and CO removal system further comprises a spraying grid, the spraying grid is arranged on the pipeline communicated between the flue gas outlet of the desulfurization and dust removal device and the flue gas inlet of the ammonia-free denitration and CO removal reactor, and the spraying grid is used for adjusting the flow field distribution of the CO entering the flue gas from the CO storage tank.

9. The ammonia-free denitration and CO removal system according to claim 7, characterized in that, The ammonia-free denitration and CO removal system further comprises a waste heat boiler, the raw material inlet of the waste heat boiler is communicated with the flue gas outlet of the ammonia-free denitration and CO removal reactor, and the waste heat boiler is used for recovering the waste heat from the flue gas of the ammonia-free denitration and CO removal reactor.

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